1. Field of the Invention
The innovation concerns a thread transport device for a textile machine having a drivable transport roller arranged on a shaft.
2. Description of the Prior Art
The most varied embodiments of thread transport devices are known. In German Patent DE-PS 946 177, a thread transport device of the type described in the Field of the Invention relates to the feeding of a elastic thread to a circular knitting machine. In this known thread transport device, the transport roller used for transporting the tread is situated on a friction disk and is supported by an arm, whose end that is oriented away from the transport roller is pivotally attached to a guide shaft. The guide shaft is aligned in such a way that, as a result of the longitudinal movement, the distance of the transport roller from the center of the friction disk can be changed, thereby also changing the circumferential speed of the transport roller. A contact pressure roller, positioned on the side of the transport roller oriented away from the friction disk abuts and is supported on a lever of the transport roller. The lever is pivoted on its end that is oriented away from the contact pressure roller. The contact pressure force of the transport roller on the friction disk, as well as the contact pressure force of the contact pressure roller on the transport roller can be changed and/or adjusted as a result of the lode weights. This known thread transport device has certain disadvantages, including a relatively complicated design and a relatively large space requirement because of use of the friction disk. That is, a relatively large space is required because only one radial beam of one friction disk can be used, but space for the remainder of the friction disk must be made available. It is also disadvantageous that the precision of the thread transport is negatively affected by a number of effects, so that, for example, a friction coefficient change results from the change of the operating temperature between the cold and the warm state of the machine. Changes with respect to humidity, temperature and air pollution also cause friction coefficient changes, and, as a result, fluctuations of the drive mechanism. The circular movement of the friction disk or the transport roller as well as the fluctuating contact pressure can also have a negative effect on the transport precision of the thread. An additional aggravation is the fact that the thread to be transported lies simply between the contact pressure roller and the transport roller and cannot be looped around the transport roller because otherwise its support by the friction roller would be negatively affected. As a result of the relatively short contact path of the thread on the transport roller and/or the contact pressure roller, the additional disadvantage results that slipping through of the thread at the transport roller can occur, thus also subjecting the supply of the thread to inaccuracies.
The object of the innovation is additionally improving a thread transport device of the type stated in the introduction in such a way that the disadvantages of the state of the art are overcome.
The object is achieved by the characterizing features of the thread transport device as described herein.